S300
ST300
Low-Cost Sensor
The S300, ST300 speed and temperature sensors are Airmar’s
lowest cost and shortest, thru-hull, speed sensors. As part of
Airmar’s Shorty™ Series, they are designed for boats with low
headroom. The plastic P371 low-profile outer housing option
is nearly flush and minimizes drag with only 5 mm (2/10”)
extending outside the hull. The plastic P398 countersunk outer
housing version mounts flush, eliminating turbulence for more
accurate speed readings.
Thru-Hull
Low-Profile
Shorty™ Series
Speed Sensors
Applications
•P371 housing—cruising sailboats and planing powerboats
•P398 housing—racing sailboats and high-speed powerboats
Features
•Shorty series low-profile is designed for fiberglass and aluminum hulls with low headroom
•Right angle cable exit offers low headroom and protection when transducer is stepped on
•Self-closing sea valve reduces waterflow when paddlewheel is removed for cleaning
•Total height is only 75 mm (2.96”)
•Fins on sides of paddlewheel cavity provide
improved accuracy in cross-flow conditions
•Housings are ABYC H-27 compliant
•Blanking plug is supplied with each unit
•Included rubber washer allows tightening of the hull nut to irregular hull surfaces
•P398 housing installation requires special cutter
•Speed only or Speed and temperature
•Available in a plastic housing only
www.airmar.com
S300, ST300
Technical Information
Per Nautical Mile
Per Knot
P371 housing
with fins
17,000 pulses
4.8 Hz
P371 housing
without fins
19,000 pulses
5.3 Hz
P398 housing
with fins
14,400 pulses
4.0 Hz
P398 housing
without fins
17,000 pulses
4.8 Hz
DIMENSIONS
ø 75 mm
(2.94”)
Nominal Pulse Rate
SPECIFICATIONS
ø 51 mm
(2.00”)
75 mm
(2.96”)
14 mm
(0.57”)
2”-12
threads
5 mm (0.20”)
P398—Flush-Mount Housing
2”-12
threads
ø 51 mm
(2.00”)
76 mm
(3.00”)
Options
• Temperature sensor
• Intelligent circuitry for linearity correction and jitter control
• No fins alongside paddlewheel
• Two-wire speed circuit
• Pulse division circuitry or other pulse rates
• Over-voltage protection (OVP)
P371—Low-Profile Housing
14 mm
(0.57”)
Weight: 0.6 kg (1.3 lb)
Speed Range: 0.1 knot to 40 knots (0.1 MPH to 46 MPH)
Supply Voltage: 5 VDC to 25 VDC
Supply Current: 100 mA at 12 VDC
Hole Diameter: 51 mm (2”)
Sensor Cable Length: 10 m (33’) standard
5 mm (0.20”)
©Airmar Technology Corporation
S300_ST300_rA
07/18/11
As Airmar constantly improves its products, all specifications are subject to change without
notice. All Airmar products are designed to provide high levels of accuracy and reliability,
however they should only be used as aids to navigation and not as a replacement for
traditional navigation aids and techniques. Shorty™ is a trademark of Airmar Technology
Corporation. Other company or product names mentioned in this document may be
trademarks or registered trademarks of their respective companies, which are not affiliated with
Airmar.